PDOStatement::debugDumpParams now returns the SQL sent to
the database, including the full, raw query (including the replaced placeholders with
their bounded values). Note, that this will only be available if emulated prepared
statements are turned on.

Before PHP 7.1.0, rewrite vars set by output_add_rewrite_var
use the same Session module trans sid output buffer. Since PHP 7.1.0,
dedicated output buffer is used,
url_rewriter.tags is used solely for output functions, url_rewriter.hosts is addedd.

Before PHP 7.1.0, rewrite vars set by output_add_rewrite_var
use the same Session module trans sid output buffer. Since PHP 7.1.0,
dedicated output buffer is used and output_reset_rewrite_vars
only removes rewrite vars defined by output_add_rewrite_var.

As of PHP 7.1.0 the handler callback is given a second argument
containing the signinfo of the specific signal. This data is only
supplied if the operating system has the signinfo_t structure.
If the OS does not implement siginfo_t NULL is supplied.

assert is now a language construct and not a
function. assertion can now be an expression.
The second parameter is now interpreted either as an
exception (if a
Throwable object is given), or as the
description supported from PHP 5.4.8 onwards.

Invalid key and iv sizes
are no longer accepted. mcrypt_decrypt will now throw
a warning and return FALSE if the inputs are invalid. Previously keys and
IVs were padded with '\0' bytes to the next valid size.

Invalid key and iv sizes
are no longer accepted. mcrypt_encrypt will now throw
a warning and return FALSE if the inputs are invalid. Previously keys and
IVs were padded with '\0' bytes to the next valid size.

When the failure string "*0" is given as the
salt, "*1" will now be returned for consistency
with other crypt implementations. Prior to this version, PHP 5.5 (and
earlier branches) would incorrectly return a DES hash.

An IntlCalendar object is allowed for
calendar.
Objects of type IntlTimeZone and
DateTimeZone are allowed for
timezone.
Invalid timezone identifiers (including empty strings) are no longer
allowed for timezone.
If NULL is given for timezone, the timezone
identifier given by date_default_timezone_get will
be used instead of ICUʼs default.

Changes were made to bring this function into line with Perl:
The "a" code now retains trailing NULL bytes.
The "A" code now strips all trailing ASCII whitespace (spaces, tabs,
newlines, carriage returns, and NULL bytes).
The "Z" code was added for NULL-padded strings, and removes trailing
NULL bytes.

The third parameter of ob_start changed from a
boolean parameter called erase
(which, if set to FALSE, would prevent the output buffer from being
deleted until the script finished executing) to an
integer parameter called flags.
Unfortunately, this results in an API compatibility break for code
written prior to PHP 5.4.0 that uses the third parameter. See
the flags example
for an example of how to handle this with code that needs to be
compatible with both.

sorting_order constants
were added. Any nonzero value caused descending order in previous versions. So
for all PHP versions, use 0 for ascending order, and 1
for descending order. An option for SCANDIR_SORT_NONE behavior did not
exist prior to PHP 5.4.0.

Constants SNMP_VALUE_PLAIN or SNMP_VALUE_LIBRARY
may be combined with SNMP_VALUE_OBJECT
resulting different way of representing contents of value
array element in return value of GET-function. If no
SNMP_VALUE_{PLAIN,LIBRARY} constant is
accompanying SNMP_VALUE_OBJECT,
SNMP_VALUE_LIBRARY is used.
Prior to 5.4.0 SNMP_VALUE_OBJECT effecively meant
SNMP_VALUE_OBJECT|SNMP_VALUE_PLAIN.

The interpretation of object oriented keywords like parent
and self has changed. Previously, calling them using the
double colon syntax would emit an E_STRICT warning because
they were interpreted as static.

The interpretation of object oriented keywords like parent
and self has changed. Previously, calling them using the
double colon syntax would emit an E_STRICT warning because
they were interpreted as static.

If this function is called from the outermost scope of a file
which has been included by calling include
or require from within a function in the
calling file, it now generates a warning and returns FALSE.

If this function is called from the outermost scope of a file
which has been included by calling include
or require from within a function in the
calling file, it now generates a warning and returns FALSE.

If this function is called from the outermost scope of a file
which has been included by calling include
or require from within a function in the
calling file, it now generates a warning and returns -1.

Prior to PHP 5.3.0, relative time formats supplied to the
time argument of strtotime
such as this week, previous week,
last week, and next week were
interpreted to mean a 7 day period relative to the current date/time, rather
than a week period of Monday through Sunday.

The categorize parameter now operates appropriately.
Previously, the categorize parameter was interpreted
as !is_null($categorize), making any value other than NULL
force the constants to be categorized.

In PHP 5 prior to 5.2.7, requesting a given occurrence of a
given weekday in a month where that weekday was the first day
of the month would incorrectly add one week to the returned
timestamp. This has been corrected in 5.2.7 and later
versions.

The default value of the length parameter was changed to NULL. A NULL length now tells the function to use the length of array. Prior to this version, a NULL length was taken to mean a zero length (nothing will be returned).

The Mersenne Twister implementation in PHP now uses a new seeding
algorithm by Richard Wagner. Identical seeds no longer produce the same
sequence of values they did in previous versions. This behavior is not
expected to change again, but it is considered unsafe to rely upon it
nonetheless.

The valid range of a timestamp is typically from Fri, 13 Dec
1901 20:45:54 GMT to Tue, 19 Jan 2038 03:14:07 GMT. (These are
the dates that correspond to the minimum and maximum values for
a 32-bit signed integer). However, before PHP 5.1.0 this range was limited
from 01-01-1970 to 19-01-2038 on some systems (e.g. Windows).

The valid range of a timestamp is typically from Fri, 13 Dec
1901 20:45:54 GMT to Tue, 19 Jan 2038 03:14:07 GMT. (These are
the dates that correspond to the minimum and maximum values for
a 32-bit signed integer). However, before PHP 5.1.0 this range was limited
from 01-01-1970 to 19-01-2038 on some systems (e.g. Windows).